1. Technical Field
The present invention relates to an inkjet printer configured so that paper dust and other foreign matter on the recording paper conveyed passed the printing position of the inkjet head does not stick on the inkjet head.
2. Related Art
One type of recording paper used for printing by inkjet printers is a continuous web of recording paper having feed holes called sprocket holes formed at a regular interval along both long edges of the paper. This type of paper is also known as tractor feed paper. Inkjet printers that print on tractor feed paper usually have a conveyance mechanism called a tractor that has sprockets for conveying tractor feed paper by repeatedly engaging and releasing the sprocket holes in tractor feed paper.
An inkjet printer with a tractor is taught, for example, in JP2005-1303A. In the inkjet printer described in JP2005-1303A, a tractor is disposed on both the upstream and downstream sides in the recording paper conveyance direction of the inkjet head printing position. A vacuum platen is also disposed to the inkjet head printing position on the recording paper conveyance path. The vacuum platen holds the recording paper flat and maintains a constant distance (platen gap) between the inkjet head and the printing surface of the recording paper by pulling the recording paper to the platen surface by means of suction.
When paper dust or other foreign matter on the recording paper sticks to the inkjet head side in this inkjet printer, the nozzles can become clogged, resulting in ink discharge problems. Much more paper dust is produced when using tractor feed paper than when using regular printing paper. More specifically, large amounts of paper dust cling to the tractor feed paper around the sprocket holes, and paper dust is easily thrown off by friction with the tractor sprocket. As a result, paper dust separates from the tractor feed paper and clings to the nozzle surface side of the inkjet head while the tractor feed paper is conveyed, and ink discharge problems, including clogged nozzles preventing ink droplet discharge, occur easily. Paper dust is also easily produced along both edges of regular printing paper.